Nature creates round objects all the time (stones in a river, a hedgehog in a ball,…), but the principle of an axle is not found as far as I know.
Nature creates round objects all the time (stones in a river, a hedgehog in a ball,…), but the principle of an axle is not found as far as I know.
No, that’s what I meant by not an axle.
But, come to think of it, we can swing our arms round and round, more than 360°.
I would argue that’s more due to the up-down and front-back limited rotations combining to form a circular mode, kinda like a Cartesian to Polar coordinate mapping
that’s reasonable.
bonus fun fact - the etymology is connected - “axle” comes from older words for “shoulder”, or “armpit”, which survives in some regional Englishes as “oxter” - the connection is apparently that you’d carry a person by putting their arms up and linking at the shoulders, much like an axle is how wheels carry a cart.
https://www.etymonline.com/word/axle